CN110376767B

CN110376767B - All-fiber wavelength selective modulator and detector of integrated optical fiber

Info

Publication number: CN110376767B
Application number: CN201910496256.9A
Authority: CN
Inventors: 余健辉; 陈哲; 刘兴豫; 朱文国; 郑华丹; 李志斌; 唐洁媛; 吴朋军
Original assignee: Jinan University
Current assignee: Jinan University
Priority date: 2019-06-10
Filing date: 2019-06-10
Publication date: 2023-03-31
Anticipated expiration: 2039-06-10
Also published as: CN110376767A

Abstract

The invention discloses an all-fiber wavelength selective modulator and detector integrated with optical fibers, which comprises a glass substrate, wherein a core-removing side polishing optical fiber is arranged on the upper side of the glass substrate, metal electrodes are arranged on two sides of a core-removing side polishing optical fiber flat area, the core-removing side polishing optical fiber flat area and the upper side of each metal electrode are covered with a graphene film, and a polymethyl methacrylate film is arranged on the upper layer of each graphene film.

Description

All-fiber wavelength selective modulator and detector of integrated optical fiber

Technical Field

The invention relates to the technical field of optical fiber devices and optical communication, in particular to an all-fiber wavelength selective modulator and detector integrating optical fibers.

Background

The photoelectric device with diversified functions is a future development trend in the optical communication technology, and the optical fiber device based on the optical fiber waveguide structure simultaneously has the functions of photoelectric detection, intensity modulation, polarization control and the like, so that the effective utilization rate of a single device is expanded. Graphene is used as a two-dimensional material with excellent performance, and has the characteristics of remarkable optical and electrical properties, high-speed carrier mobility and the like, so that the graphene has excellent performance in a functional photoelectric device.

The existing similar all-fiber devices can only realize single function. Patent application No. 201120571231.X discloses a graphene electro-optic modulator based on a D-type optical fiber. The structure is that a graphene film is laid on the surface of a D-type optical fiber, meanwhile, a metal electrode and a lead wire are prepared at one end of the graphene film, an insulating layer is plated on the graphene film and is plated beside the metal electrode and the lead wire on the graphene film, the insulating layer is aluminum trioxide or other insulating layers with high dielectric constants, the metal electrode and the lead wire are conductive electrodes, and the conductive electrodes are Au or Pt. The defects of the patent are that the light utilization rate of the device is low due to structural defects, and the performances of polarization control and light intensity modulation are poor. Meanwhile, it is impossible to estimate whether it has multi-functional characteristics.

Disclosure of Invention

In view of the above, the present invention provides an all-fiber wavelength selective modulator and detector integrated with optical fiber, which combines a graphene film, a polymethyl methacrylate film, a core-removed side polished fiber waveguide structure, and parallel metal electrodes, so that the all-fiber wavelength selective modulator and detector has wavelength selective electro-optical modulation and photo-electrical detection functions to achieve the purpose of use.

The all-fiber wavelength selective modulator and the detector of the integrated optical fiber comprise a glass substrate, a core-removing side polishing optical fiber is arranged on the upper side of the glass substrate, metal electrodes are arranged on two sides of a flat area of the core-removing side polishing optical fiber, a graphene film is arranged on the flat area and the upper side of the metal electrodes in a covering mode, and a polymethyl methacrylate film is arranged on the upper layer of the graphene film.

In the technical scheme, the used waveguide is a core-removed side-polished optical fiber, and the core-removed side-polished optical fiber is a region in which an evanescent wave field exists by reducing the cladding thickness of the optical fiber by a physical polishing method, namely, the fiber core of the optical fiber is polished off, so that a leakage window for transmitting the optical evanescent wave field by a fiber-core-free structure is formed. At this "leakage window", there is the possibility to excite, control, modulate the transmitted light in the fiber core using evanescent wave fields. Compared with a fiber core-provided side polishing optical fiber, the core-removed side polishing optical fiber used in the method has a stronger evanescent field, and further enhances the coupling efficiency of an optical fiber transmission optical field and a graphene film, so that the action strength of light and the graphene film is enhanced; in addition, different with the side polishing optical fiber that has the fibre core, this patent uses decoring side polishing optical fiber transmission light field and polymethyl methacrylate film to produce wavelength selectivity resonance coupling, and then forms wavelength selectivity's light field and graphene film interact, and then realize the optical wavelength selectivity modulation effect that this patent proposed, secondly, graphite alkene is set up between coreless side polishing optical fiber and polymethyl methacrylate film, the polymethyl methacrylate film is great than the optical fiber refractive index, consequently optical fiber transmission light field center is drawn to the polymethyl methacrylate film, and then further strengthen the interact between graphite alkene and the transmission light field, the modulation depth and the modulation efficiency of electrooptical modulation have been strengthened, improve the performance of this patent electrooptical modulation. Finally, the interaction length of the light and the graphene film is determined by the flat area and the length of the graphene film, and the flat area has the advantage that any length can be selected; this patent is direct to be prepared on optic fibre, the coupling difficult problem of waveguide structure and optic fibre has been avoided, insertion loss is low, this patent is integrated can also realize on-line monitoring's purpose at optic fibre communication's in-process on optic fibre, and two metal electrodes are located the plateau both sides, the upside covers the graphite alkene film, this kind of metal electrode structure can be along the controllable design of light transmission waveguide direction as required length, effective length is longer more, light and graphite alkene film coupling intensity are big more, this kind of structure is used for producing the electric field relevant electric capacity with penetrable material sample and sensitive coating, play high efficiency control's effect, through polishing the optic fibre direct contact with coring side, the side of coring is polished and is propagated light direct and graphite alkene film coupling in the optic fibre, and absorb the emergence effect by graphite alkene film.

Preferably, the flat region has a thickness of 45um to 50um.

Preferably, the length of the flat zone is 10mm to 15mm.

According to the technical scheme, the thickness and the length of the flat area of the core-removed side polished optical fiber are selected, so that the action strength of the graphene film and the fiber core is enhanced, and the utilization rate of evanescent light is improved.

Preferably, the thickness of the polymethyl methacrylate film is 400nm to 3000nm.

Preferably, the graphene film is single-layer graphene.

Preferably, the material of the metal electrode is gold, copper, aluminum, platinum, molybdenum or palladium.

Preferably, the distance between the two metal electrodes is 20um-200um.

The spacing distance of the metal electrodes has a great influence on the overall performance index of the multifunctional device. Generally, the electrodes are spaced apart by a small distance, and the electric field intensity in the flat region is increased, which affects the performance of the device. Therefore, the performance of the patent can be improved by optimizing the spacing distance parameter of the metal electrodes, and when the electrode structure is applied to different detection fields, the electrode structure with different structural parameters may need to be used.

Preferably, the thickness of the metal electrode is 30nm to 100nm.

The thickness of the metal electrode can have great influence on the overall performance of the patent. When the thickness of the metal electrode is reduced to be below the micron or nanometer level, the weak resistance change at two ends of the metal electrode can be sensitively detected, and the sensitivity of the detector is obviously improved. Therefore, the overall performance of the patent can be improved by optimizing the thickness parameters of the metal electrode, and when the electrode structure is applied to different detection fields, the electrode structure with different structural parameters may need to be used.

Preferably, the length of the optical fiber polished by the metal electrode along the coring side edge is 3cm-6cm, and the width of the metal electrode is 0.5cm-1.2cm.

Preferably, the glass substrate is a glass slide for scientific research experiments.

Compared with the prior art, the invention has the following beneficial effects: the evanescent field of the core-removed side-polished optical fiber is coupled into the polymethyl methacrylate film, so that the contact with the graphene film is enhanced, and the modulation efficiency is improved. When modulation voltage is added, the graphene film is conductive and generates heat, so that the refractive index of the polymethyl methacrylate film is changed, the coupling efficiency is changed, the intensity of the graphene film contacting with an evanescent field is changed, the absorption efficiency of the graphene film to light is changed, and light intensity modulation is realized. And because of the difference of the coupling efficiency of different wavelengths, the voltage is adjusted, so that the device can carry out electro-optical modulation on the wavelength with high coupling efficiency, thereby realizing wavelength selective modulation. Meanwhile, the photoelectric detection of wavelength selection is also an innovation of the research.

The all-fiber wavelength selective modulator and the detector of the integrated optical fiber realize the integration of the electro-optical modulation and the photoelectric detection functions of wavelength selection on all-fiber devices. The method is applied to an optical fiber communication system, can greatly reduce the complexity of the system, and provides a method for a more efficient communication system. Meanwhile, the design of the all-fiber realizes the fiber communication device with low insertion loss, high transmission efficiency and high communication quality, and greatly improves the communication quality.

Drawings

FIG. 1 is a diagram of an integrated fiber-optic all-fiber wavelength selective modulator and detector in accordance with the present invention.

FIG. 2 is a cross-sectional view of a core-removed side-polished fiber covered with a graphene film according to the present invention.

Fig. 3 is a schematic diagram showing the electro-optic modulation performance of the present invention.

FIG. 4 is a schematic diagram showing the polarization characteristics of the present invention.

Fig. 5 is a schematic diagram of the performance of the photoelectric detection according to the present invention.

Detailed Description

The present invention will be further described with reference to the following embodiments. Wherein like reference numerals correspond to like elements throughout the several views of the embodiments of the present invention, and are used for illustrative purposes only and are not to be construed as limiting the present invention; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; the terms "upper", "lower", "left", "right", and the like in the embodiments of the present invention indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and do not indicate or imply that the indicated device or element must have a specific orientation or be configured in a specific orientation, and specific meanings of the terms may be understood according to specific situations by those skilled in the art.

Examples

As shown in fig. 1 and 2, the all-fiber wavelength selective modulator and detector integrated with an optical fiber of the present invention includes a glass substrate 1, a core-removed side polishing optical fiber 2 is disposed on an upper side of the glass substrate 1, metal electrodes 4 are disposed on two sides of a flat region 3 of the core-removed side polishing optical fiber 2, a graphene film 5 is disposed on the flat region 3 and the upper sides of the metal electrodes 4 in a covering manner, a polymethyl methacrylate film 6 is disposed on an upper layer of the graphene film 5, and two independent metal electrodes 4 are disposed between the glass substrate 1 and the graphene film 5 and are arranged on two sides of the flat region 3. The temperature of the graphene film 5 with the polymethyl methacrylate film 6 is changed by changing the driving voltage applied to the two ends of the two independent metal electrodes 4, so that the absorption of the graphene film 5 on the transmission light intensity with specific wavelength in the optical fiber is regulated and controlled, and the wavelength selection modulation is realized.

The waveguide that adopts in this patent is coring side polishing and grinding optic fibre 2, and in single mode fiber (diameter be 125um, fibre core 8 um), the optical fiber cladding of enough thickness has guaranteed the light field of propagating in the fibre core and can not reveal to the optic fibre outside at the energy of the evanescent wave field in the optical fiber cladding usually. The core-removed side-polished optical fiber 2 is polished physically to reduce the thickness of the cladding of the optical fiber to the region where the evanescent wave field exists, i.e. to polish off the fiber core of the optical fiber, thereby forming a leakage window for transmitting the optical evanescent wave field in a fiber core-free structure. At this "leakage window", there is the possibility to excite, control, modulate the transmitted light in the fiber core using evanescent wave fields. According to the optical fiber system, the coupling efficiency of the core-removed side polished optical fiber 2 in the coupling process of the optical fiber system is high, and a strong evanescent field is generated when light passes through a leakage window, so that the action strength of the light and the graphene film 5 is increased, and the modulation effect of wavelength selection of the optical fiber system is further increased; secondly, the interaction length of the light and the graphene film 5 is determined by the lengths of the flat area 3 and the graphene film 5, and the flat area 3 has the advantage that any length can be selected; finally, this patent is direct to be prepared on optic fibre, has avoided the coupling difficult problem of waveguide structure and optic fibre, and insertion loss is low, and the integrated purpose that can also realize on-line monitoring at fiber communication's in-process on optic fibre of this patent, and the side of coring is polished the optic fibre and is remained thickness and be 45um to 50um, and polishing district length is 10 to 15mm.

In the present embodiment, the polymethyl methacrylate thin film 6 and the graphene thin film 5 are formed by stacking and arranging the polymethyl methacrylate thin film 6 and the graphene thin film 5, wherein the graphene thin film 5 is graphene grown on a Cu foil by Chemical Vapor Deposition (CVD), and the polymethyl methacrylate thin film 6 is a solution prepared by dissolving polymethyl methacrylate in anisole and uniformly stirring. Covering a graphene film 5 on the flat area 3, then covering the graphene film 5 by a wet polymethyl methacrylate transfer technology, wherein the graphene film is a single-layer or few-layer graphene film 5 grown by a Chemical Vapor Deposition (CVD) method, and the required range of the number of layers of the graphene film 5 manufactured by the CVD method is 1-9. The thickness of the polymethyl methacrylate film 6 is required to be within the following range: 400 to 3000nm. With such a layout, light transmitted in the cored side polished fiber 2 can be directly coupled with the graphene film 5. Simultaneously, based on graphite alkene film 5 as a novel two-dimensional atomic crystal thin film material, possess and have excellent optics, electrical property, characteristics such as super high thermal conductivity and ultrafast carrier mobility, can consequently make this patent produce comparatively efficient effect intensity.

The metal electrodes 4 are symmetrically arranged on two sides of the flat area 3, and the metal electrodes 4 on two sides are tiled between the glass substrate 1 and the graphene film 5. The electrode structure can be designed along the direction of the optical transmission waveguide according to the required controllable length, generally speaking, the longer the effective length is, the stronger the coupling strength of light and the graphene film 5 is, and the structure is used for generating capacitance related to an electric field capable of penetrating a material sample and a sensitive coating, so that the function of controlling the patent efficiently is achieved. The metal electrode 4 is made of gold, and it is clear to those skilled in the art that the metal electrode 4 may also be made of gold or copper or platinum or molybdenum or palladium, and the resistance of the patent is reduced by using a metal with small resistance, so as to achieve the purpose of low voltage and high responsivity. The distance is 20-200um between the metal electrode 4 for the profile layout is transmitted the smooth side edge of coring and is ground optic fibre 2, metal electrode 4 thickness scope is 30nm-100nm, and metal electrode 4 thickness all has very big influence to metal electrode 4's performance index, reduces to below micron or the nanometer magnitude when its thickness size, and the weak resistance change in metal electrode 4 both ends can be detected sensitively, and the sensitivity of the all-fiber wavelength selective modulator of an integrated optical fibre of this patent and detector can show the improvement. This patent metal electrode 4 can improve the holistic performance of this patent through selecting above-mentioned structural parameter, when being applied to different detection areas, probably need use different structural parameter's electrode structure.

Various traditional functional devices based on graphene adopt silicon waveguide structures, and the device manufactured by the silicon waveguide structures has the defect of low coupling efficiency in the coupling process with an optical fiber system; in addition, the refractive index of silicon is greater than that of silicon dioxide (the main material of the optical fiber), so that a weaker evanescent field is generated when light passes through the silicon waveguide, the action strength of the light and graphene is reduced, and the performance of a device is influenced; meanwhile, because of the self limitation of the silicon waveguide, the silicon waveguide has great limitation on the size of manufacture, particularly the length is generally short, and the advantage that the optical fiber can select any length is obviously reflected; in addition, the all-fiber wavelength selective modulator and the detector integrated with the optical fiber, which are integrated on the optical fiber, can also achieve the purpose of online monitoring in the process of optical fiber communication. And the metal electrode adopting a structure that the polymethyl methacrylate film 6 and the graphene film 5 are stacked and arranged and a gold material realizes efficient multifunctional characteristics.

Based on all the above backgrounds and ideas, the present patent proposes a structural layout of an all-fiber wavelength selective modulator and a detector integrated with an optical fiber, which can produce multifunctional effects: fig. 3 is a schematic diagram of the electro-optic modulation characteristics, which shows the modulation of the transmission light intensity in the optical fiber by the bias voltage at the two ends of the metal electrode 4 when the input light is 1539nm and 1541nm, respectively. Of which 1539nm has a modulation depth of about 6dB and 1541nm has a modulation depth of about 1.7 dB. Fig. 4 is a schematic diagram showing polarization characteristics, the range of the influence of polarization on light intensity under the same voltage is 1.5-6.2dB, and the voltage has selective regulation and control characteristics on light wavelength under the same polarization. Fig. 5 is a schematic diagram of a photodetection characteristic, which shows that the generation of photocurrent occurs when different bias voltages and optical powers change, and the photocurrent has a response value.

This patent provides an all-fiber wavelength selective modulator and detector of integrated optical fiber through the coupling of the side of coring 2 evanescent fields of polishing and grinding optic fibre into polymethyl methacrylate film 6, has strengthened the contact with graphite alkene film 5, has improved modulation efficiency. When modulation voltage is added, the graphene film 5 conducts electricity and heats, so that the refractive index of the polymethyl methacrylate film 6 changes, the coupling efficiency is changed, the intensity of the evanescent field contacted by the graphene film 5 changes, the absorption efficiency of the graphene film 5 to light is changed, and light intensity modulation is achieved. And because the coupling efficiency of different wavelengths is different, the voltage is adjusted, so that the electro-optical modulation can be performed on the wavelength with high coupling efficiency, and the wavelength selective modulation is realized. Meanwhile, the photoelectric detection of wavelength selection is also an innovation of the research.

The utility model provides an all-fiber wavelength selective modulator and detector of integrated optic fibre, realize integrating the electrooptical modulation of wavelength selection, photoelectric detection function on all-fiber device. The method is applied to an optical fiber communication system, can greatly reduce the complexity of the system, and provides a method for a more efficient communication system. Meanwhile, the design of the all-fiber realizes the fiber communication device with low insertion loss, high transmission efficiency and high communication quality, greatly improves the communication quality and really achieves the aim of the invention.

It is to be understood that the present invention is not limited to the above embodiments. Variations and modifications are possible in light of the above teachings, by those of ordinary skill in the art, without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims of the present invention.

Claims

1. The all-fiber wavelength selective modulator and detector of the integrated optical fiber are characterized by comprising a glass substrate (1), a core-removing side edge polishing optical fiber (2) is arranged on the upper side of the glass substrate (1), metal electrodes (4) are arranged on two sides of a flat area (3) of the core-removing side edge polishing optical fiber (2), a graphene film (5) is covered on the upper sides of the flat area (3) and the metal electrodes (4), and a polymethyl methacrylate film (6) is arranged on the upper layer of the graphene film (5);

the thickness of the flat area (3) is 45-50 um;

the length of the flat area (3) is 10mm-15mm.

2. The all-fiber wavelength selective modulator and detector of claim 1, wherein said polymethylmethacrylate film (6) has a thickness of 400nm to 3000nm.

3. The all-fiber wavelength selective modulator and detector of claim 1, wherein said graphene film (5) is single-layer graphene.

4. The all-fiber wavelength selective modulator and detector according to any one of claims 1-3, wherein the metal electrode (4) is made of gold, copper, aluminum, platinum, molybdenum, or palladium.

5. An all-fiber wavelength selective modulator and detector according to any one of claims 1-3, wherein the distance between said two metal electrodes (4) is 20-200 um.

6. An all-fiber wavelength selective modulator and detector integrated with an optical fiber according to any one of claims 1 to 3, wherein said metal electrode (4) has a thickness of 30nm to 100nm.

7. The all-fiber wavelength selective modulator and detector of any one of claims 1-3, wherein said metal electrode (4) is polished along the cored-out side of the fiber (2) to a length of 3cm-6cm, and said metal electrode (4) has a width of 0.5cm-1.2cm.

8. An all-fiber wavelength selective modulator and detector integrated with optical fibers according to any one of claims 1 to 3, wherein said glass substrate (1) is a glass slide for scientific research.